Sam Mendes’ buzzy new drama, “Empire of Light,” is a story about a single woman with mental health issues. The script – Mendes’ first solo writing credit – was informed by his mother’s struggles while he was growing up in the U.K.

“As the parent of young children myself, you’re always reflecting on how you were parented,” Mendes told Variety at the Los Angeles premiere of the film. “Increasingly, my mother’s struggles with mental illness, and her raising me as an only child, seemed heroic. I wanted to write about that.”

Mendes says his mother has seen the film, but he didn’t tell her how the script came to be beforehand. “She enjoyed it,” Mendes said. “I just wanted her to go in with no idea. It was a big moment. It was moving.”

The film is not autobiographical. Instead of playing a mom raising a child, Olivia Colman stars in the film as a single woman with mental health issues who works in a movie theater in the 1980s. The cast also includes Colin Firth and Michael Ward.  

Mendes and his producing partner Pippa Harris have known each other since childhood, making the film’s subject matter even more personal.

“I was a bit nervous, to be honest,” Harris said of her initial reaction to Mendes’ film pitch. “We grew up together, so I knew some of what he’d been through as a kid and it was quite tough. I was nervous about how that would translate, but what I think he’s done seamlessly is to use the mental health journey of his mother but create a completely different character.”

Harris praised Mendes for his authentic storytelling, even though the script was a work of fiction. “Those themes of mental health and how you deal with someone going through an episode like that ring entirely true because it’s based on what he faced,” she said.

In one scene, Colman’s character has a manic episode in her apartment. “I think it was quite tough for Sam to shoot because it was so authentic, down to the detail of a milk bottle upside down on a table,” Harris said. “You think, ‘What a strange piece of set decoration.’ But Sam had done that deliberately because it’s what he remembered.”

“Empire of Light” hits theaters Dec. 9.